Authenticating a painting believed to be the work of a master is a combination of science and art. Documentary producer Jo Ann Caplin heads to Europe to observe as experts investigate whether La Bella Principessa is in fact the work of Leonardo da Vinci.

Before becoming a synonym for cinema, celluloid was never quite a star attraction. But the first successful synthetic plastic played a subtle role in shaping consumer culture.

Let’s go to the library! This week we take a field trip to that venerable institution where great reading abounds and shushing up is de rigueur.

In the fight against breast cancer, entrenched interests and outmoded ideas may be hurting patients.

 The rise, fall, and resurrection of the humble leech.

Remember the fire-fighting mascot Smokey Bear? Meet Johnny Horizon, his little-remembered, pollution-fighting counterpart.